Now this one is simple. I think that people with a moderate rank (Veteran and up) should be able to use "/playtime" or perhaps "/stats" (unless /stats gives away personal information such as IP).
/playtime would show how many hours total, that a certain player has played, and it would also show how long you have played for (moderators can already do this).
The command would be /playtime <player>, and it would look something like this:
DawnStrike
Total playtime: 50h
Member for: 326d
I think that players who aren't staff should be able to do this, because it doesn't give out any personal information that could be used against them, and it tells you a little bit more about that person. It would also tell you if they are a frequent member.
I think that should be added. I have always wanted to see how long i have played for so that i can see how addicted i am :P